Dietary fiber isolated from sweet potato residues promotes healthy gut microbiome profile

Authors: LU, MAN - Jiangsu University; LI, XUEZHI - Jiangsu University; ZHOU, SHENMIN - Jiangsu University; Wang, Thomas - Tom; ZHOU, SIHAN - Jiangsu University; YANG, KUNLONG - Jiangsu University; LI, YOUNGXIN - Jiangsu University; TIAN, JUN - Jiangsu University; WANG, JING - Jiangsu University

Submitted to: Food and Function
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/13/2019
Publication Date: 1/29/2020
Citation: Lu, M., Li, X., Zhou, S., Wang, T.T., Zhou, S., Yang, K., Li, Y., Tian, J., Wang, J. 2020. Dietary fiber isolated from sweet potato residues promotes healthy gut microbiome profile. Food and Function. 11, 689-699. https://doi.org/10.1039/c9fo01009b.
DOI: https://doi.org/10.1039/c9fo01009b

Interpretive Summary: Fiber is an important component in food that can promote health. This study investigated the impact of dietary fiber from sweet potato residue (SPDF) on the diversity of gut microbiota. An in vitro batch culture system simulating the human gut was used to understand the prebiotic role of SPDF. The results showed that SPDF mediated a significant increase in the concentrations of Bifidobacterium and Lactobacillus and induced significant decreases of Enterobacillus, Clostridium perfringens and Bacteroides. The prebiotic index and Bifidobacterium/ Enterobacillus value were also significantly increased in SPDF groups compared to the control group, suggesting that SPDF had prebiotic effects. Furthermore, to investigate the effects of SPDF on the intestinal microecosystem, the diets containing different concentrations of SPDF were used to feed Wistar rats for 4 weeks. 16S rRNA gene sequencing, short chain fatty acid quantification and physiochemical properties analysis in the rat feces were then conducted. The results showed that SPDF significantly increased Bacteroidetes to Firmicutes ratio at the phylum level and the amount of Akkermansia was also increased at the genus level, which was confirmed by qRT-PCR. The production of propionate and butyrate in the rat feces of 3% and 15% SPDF groups were both higher than that in the control group, which was further confirmed by the decrease of pH. Additionally, SPDF supplementation in this study resulted in higher villus height to fossae depth ratio, which indicated improved digestion and absorption in the GI tract. Our findings support the utilization of SPDF from sweet potato residue in the development of potentially prebiotic food products for improving intestinal health. This study provides novel information on sweet potato fiber on the gut microbiome. The information will benefit basic, translational scientists, as well as farmers and consumers who are interested in sweet potato by-products for health promotion.

Technical Abstract: This study investigated the impact of dietary fiber from sweet potato residue (SPDF) on the diversity of gut microbiota. An in vitro batch culture system simulating the human gut was used to understand the prebiotic role of SPDF. The results showed that SPDF mediated a significant increase in the concentrations of Bifidobacterium and Lactobacillus; whereas they induced significant decreases of Enterobacillus, Clostridium perfringens and Bacteroides. The prebiotic index and obacterium/ Enterobacillus value were also significantly increased in SPDF groups compared to the control group, suggesting that SPDF had prebiotic effects. Furthermore, to investigate the effects of SPDF on the intestinal microecosystem, the diets containing different concentrations of SPDF were used to feed Wistar rats for 4 weeks. 16S rRNA gene sequencing, short chain fatty acid quantification and physiochemical properties analysis in the rat feces were then conducted. The results showed that SPDF significantly increased Bacteroidetes to Firmicutes ratio at the phylum level and the amount of Akkermansia was also increased at the genus level, which was confirmed by qRT-PCR. The production of propionate and butyrate in the rat feces of 3% and 15% SPDF groups were both higher than that in the control group, which was further confirmed by the decrease of pH. Additionally, SPDF supplementation in this study resulted in higher villus height to fossae depth ratio, which indicated improved digestion and absorption in the GI tract. Our findings support the utilization of SPDF from sweet potato residue in the development of potentially prebiotic food products for improving intestinal health.